Liquid sprayer



Feb. 8 1.949. H. G. wALTr-:Rs

LIQUID SPRAYER Filed Jan. 18, 1945 IRNEY Patented Feb. 8, 1949 UNITED STATES PATENT DFFICE LIQUID SPRAYER Harold G. Walters, `United States Army, Richmond, Ind.

amended April 30, 1928; 370 O. G. 757) The invention described herein, if patented, may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

My invention relates to sprayers operated by a hot atomizing fluid and more particularly to an improved spray nozzle so constructed that the spray liquid is heated by the atomizing fluid While these fluids are passing through the nozzle, means being provided for securing uniform heating of the spray liquid before it reaches the nozzle tip.

In sprayers of the type used in spraying insecticides, disinfectants and other liquid spray compounds the liquid is drawn through a` nozzle by a motivating or atomizing fluid such as steam, air or water which is ejected from an aspiratlng outlet in the gun at high velocity andl at that point strikes the spray liquid at high velocity and in such a manner that it is atomized and intimately mixed with the atomizing uid discharging from the nozzle of the gun.

In the spraying of many insecticides and disinfectants, it has been found that heating of the compound before it reaches the nozzle tip assists greatly in securing a more finely atomized spray. Although various types of nozzles can be found in the prior art and some of these could be adapted for heating the spray compound as it passes through the nozzle, yet none are effective to providevthe degree and uniformity of heating desired in the spraying of insecticide and dislnfectants. It is vtherefore an object of this invention to provide a new and improved sprayer in which a maximum and uniform heating of the spraying compound is secured while it is passing through the spray nozzle.

Another object of the invention is the provision of a new and improved sprayer in which a maximum heating of the spraying compound is secured from the hot atomizing uid.

Another object of the invention is the provision of a new and improved sprayer having means for agitating the spray uid in its passage to the nozzle tip to effect more uniform heating of the liquid, the agitating means also acting as a heat exchange element to increase the heating of the uid.

Another object of the invention is the provision of a new and improved sprayer which is durable and compact in construction and inexpensive to manufacture so that it may be permanenty installed at very little cost in locations Where relatively frequent spraying is necessary.

Another object of the invention is the provision of a spray nozzle in which the atomizing fluid sur.. rounds a spray liquid delivery conduit and is caused to flow in a tortuous path about the conduit to provide maximum contact between the hot atomizing uid and conduit and more effective heating of the conduit and fluid therein.

Another object of the invention is the provision of the new and improved sprayer having a heat exchange element secured about the spray fluid supply conduit in the nozzle to provide more effective heating of the fluid in the conduit by the atomizing agent.

Although the embodiment which I have described for the purpose of illustrating the invention is a preferred form, it will be obvious as the description proceeds that changes in the form and arrangement of parts may be made without departing from the scope and spirit of the invention. In the drawings Figure 1 is a fragmentary view partly in section showing -my sprayer permanently secured toxa support such as the wall of a room. f

Figure 2 is a horizontal section of the spray nozzle of my device.

Figure 3 is a cross-sectional view taken on the line 3-3 of Figure 2.

Figure 4 is a cross-sectional view taken on the line 4-4 of Figure 2.

Referring to Figure l, the sprayer includes a spray nozzle assembly I0, a reservoir II for containing the liquid spray compound, a tube I2 for delivering spray compound from the reservoir to the spray nozzle and a bracket I3 secured to the top of the reservoir for supporting the nozzle in operative position and for securing the entire assembly to the wall of a room or any other permanent support. v

The nozzle I0 includes a combined heat exchange element and liquid spray supply conduit I4, machined from brass or other suitable metal or made from a casting machined on certain surfaces to provide a close iit with the inner surface of a tubular housing I5 which incloses the heat exchange element I4. A separate cap I6 is provided for closing the forward end of the housing.

4o The heat exchange element I4 comprises an eloning a conduit or passageway of large cross-section for liquid insecticide which terminates in a conically shaped forward end 2| communicating at its apex with a greatly reduced bore 22 extending through the reducedend I9 of the said heating element yto form the discharge outlet therefor.

Disposed upon the enlarged tubular portion of the heat exchange element Il arefa plurality of spaced slotted fins 23 which are concentric therewith and are machined on their outer surfaces 24 to provide a snug fit with the inner surface 25 of the housing I5. Radial slots 26 are formed inA audaci each of these fins to provide a passageway for the flow of rsteam through the housing and to the cap I6, the slots on adjacent fins being diametrically opposed as shown in Figures 3 and 4 so that the atomizing fluid in passing from the space between two fins to the succeeding space strikes the side of the succeeding fin and must flow around the .heat exchange element I4 to reach the slot in that n. It will be obvious that by forcing the hot atomizing fluid to flow in a zigzag path that the contact between the atomizing fluid and the fins and heat exchange element is increased so that more effective heating of both is secured. The fins 25 present a. large contact surface' to the hot atomizing fluid and thus are adapted to absorb large quantities of heat therefrom which in turn ls conducted to the heat exchange element I4 further increasing the heating thereof and of the spray liquid passing therethrough.

Housed within the heat exchange element I4 is a helical coil spring 21 which abuts against the forward end 2| of the axial bore 20 of the said element and is held in position by the inner end of anr elbow fitting 28 secured in the threaded outer end of the bore 20. This fitting is secured to the spray delivery tube I2 by a coupling 29. A screen 30 may be interposed between the delivery tube I2 and the fitting 28 to prevent the passage of impurities which may be present in the spray compound into the bore 20. The coils of .the spring 21 are in contact with the walls of the bore 20 and absorb heat therefrom so that the spring acts not only as an agitator of the spray liquid flowing through the bore, but also as a heat exchanger for imparting additional heat to the iiuid.

The combined heat exchange element and tubular supply conduit I4 are enclosed by the tv;- bular housing I and the conical 'shaped hollow cap I6 which has a base 3|? and an apex 32 provided with an aperture 33 extending through the cap. The base of the cap I6 has a reduced portionl 34 adapted to be received in the forward end of the housing I5 in -snug engagement therewith, and an annular shoulder 35 againstwhich the forward end of the housing I5 abuts when the cap is in position in the housing. The reduced tip I9 of the heat exchange element I`4 extends through the aperture 33 in the cap I6 and terminates in the plane of the outer edge of this opening which is of slightly larger diameter than the tip, providing an annular passageway 36 of small crosssectional area between the tip and the interior of the cap. Both of these parts are machined to accurately define the area of this passageway and provide an aspirating outlet for the nozzle.

To assemble the parts, the cap I6 is arranged in position with its base 3l abutting against the foremost fin 23 on the heat exchange element I4 atomizing fluid under pressure. The inner face of the boss is concave in form to correspond to the outer surface of the housing and is secured to the housing by brazing or welding or by any other suitable means which will provide a leakproof union between the housing and boss.

Any container of appropriate size may be used as a reservoir for spray liquid, but I have found that an ordinary glass Mason jar makes a very suitable reservoir in those installations Where the sprayer is to be permanently secured in a room. Such jars areprovided with a metallic cap 42 which is threaded onto the neck of the jar and has a fiat top surface which forms an ideal base to which the horizontally extending arm 43 of the bracket I3 may be secured by means of a rivet 45 or any other suitable means. In assembled relation the forward end of the nozzle I0 is cured thereto in any suitable fashion to hold the nozzle securely in position. With the nozzle mounted in the position described, and shown in Figure 1, the spray delivery tube I2 projects upwardly from the reservoir through an aperture 46 in the edge of the cap and a coinciding aperture 41 in the horizontal arm of the bracket I3. In order to provide a rigid assembly the spray delivery tube I2 may be welded or soldered to the cap 42 and bracket I3 after the correct positioning thereof has been secured,

A downwardly extending arm 48 is also provided on the bracket and may be secured to the wall of a room or to any other suitable means for v permanently mounting the sprayer in a room. If

into the cap and the sprayer is then ready for use.l

Although not limited to such use, the sprayer described herein is particularly suitable for installation in exterminator systems for various types of rooms that require frequent spraying such as storage rooms for furs and other products that are attacked by insects or it may be used to advantage in buildings for human occupancy which are located in areas infested with disease bearing insects such as malaria mosquitoes. When it is desired to spray a room, the nozzle is connected to a source of steam having a pressure of and the tubular housing I5 is pressed over the heating element and reduced portion 34 of cap to hold the parts in assembled relation. If desired the seams between the cap and the housing and the flange I3 and the housing may be' sealed by brazing or soldering to assure a leakproof union :between these parts so that steam or other atomizing fluid cannot escape through these seams.

An inlet to the space within the' housing is secured through a cylindrical boss or fitting 31 which is permanently secured to the outer sur-face of the housing at its rear end and has an aperture 39 extending axially therethrough and registering with an aperture 39 in the housing I5. The

aperture 33 in the boss is threaded from its outer s Aend for a portion of its length and receives the threaded tip 40 of a conduit 4I for supplying from 30 to 50 pounds per square inch by the flexible hose 4I having the tip 40 which is threaded into the boss 31. A manually operated valve which is not shown may be provided in the hose for regulating the pressure of the steam and thereby determining the rate of operation. In this manner it is possible to thoroughly spray a vroom of about 25,000 cubic feet capacity in 5 or 6 minutes using a single sprayer.

Steam from the hose 4I enters the space in the jacket I5 between the flange I8 and the first iin 23 through the fitting 31 and the aperture 39 in the housing and passes from this space through the slot 26 in the top of the first fin to the space between the first and second fin and from there through the slot 26 in the lower part of the second fin and in this zigzag fashion through the iacketuntil it emerges through the slot 26 inthe forward fin 23 into the cap I6. In this manner maximum contact between the steam and the heat exchange element and the most effective heating of the spray liquid is secured so that it is at a high temperature when it reaches the tip I9. Escape from the cap is limited to the annular passageway 36 between the tubular tip I9 and the edges of the opening 33. Because of the relatively reduced cross-sectional area of pas.

sageway 3B the velocity of the steam as it escapes is increased to an extent suiiicient to create and maintain a vacuum at the end of the tubular tip as long as steam flows through'the motivating and atomizing fluid, it will be obvious that my spray nozzle is suitable for use with other types of spray compounds which normally exist in liquid form, and that fluids other than steam for example hot water or hot air may be used in operating these sprayers. Spray nozzles are commonly used in oil burners to vaporize the viscous liquid fuel used in such burners and my nozzle could readily be adapted for use in oil burners where it would be particularly effective in cold weather because fuel oil tends to become more viscous at such times. Other applications of my device will suggest themselves, particularly where it becomes necessary to atomize a viscous material which is more readily atomized at elevated temperatures. The embodiment' shown and described is intended merely to exemplify one form of my invention and I do not desire to have it limited thereby except insofar as it is limited' by the appended claims.

Iclaim:

1. A liquid atomizing device comprising (1) a conduit communicating with a liquid reservoir, said conduit having an elongated straight tubular wall of large cross-section for the conveyance of said liquid, (2) spiral means coaxial with and interiorly of said conduit and in heat exchange relation With the tubular Wall of said conduit for agitating and heating the liquid conveyed through said conduit, 3) a tubular outlet of small cross-section communicating with said conduit, (4) an elongated tubular housing for the conveyance of atomizing uid under pressure, said housing surrounding said conduit and communicating veyed through said conduit, (3) a tubular outlet of small cross-section communicating with said conduit, (4) an elongated tubular housing for the conveyance of atomizing fluid under pressure, said housing surrounding said conduit and communicating with a source of supply of said atomizingfluid, (5) said housing having a constricted outlet portion surrounding said firstnamed outlet and terminating in the same plane as said first-named outlet in aspirating relation therewith, and (6) a plurality of spaced heatconductive ns exteriorly on said conduit and extending into said housing, said fins being slotted alternately at diamctrically opposite points for defining a zigzag path of iiow for said atomizing fluid through said housing to said aspirating outlet from side to side of the housing and around said conduit to effect maximum contact 4between said atomizing fluid and said conduit and to obtain optimum heating thereof and of the liquid passing through said conduit.

3. A liquid atomizing device comprising (1 a liquid reservoir, (2) a conduit communicating with said liquid reservoir, said conduit having an elongated straight tubular Wall of large crosssection for the conveyance of said liquid, (3) spiral means coaxial with and interiorly of said conduit and in heat exchange relation with the tubular wall of said conduit for agitating and heating the liquid conveyed through said conduit, (4) a tubular outlet of small cross-section communicating with said conduit, (5) an elongated tubular housing for the conveyance of atomizing fluid under pressure, said housing surheating thereof and of the liquid passing through with a source of supply of said atomizing fluid, l

(5) said housing having a. constricted outlet portion surrounding said first-named outlet and terminating in the same plane as said firstnamed outlet in aspirating relation therewith, and (6) heat conductive means exteriorly on said conduit and extending into said housing for defining a path of flow for said atomizing fluid through said housing to said aspirating outlet from side to side of the housing and around said conduit to effect maximum contact between said atomizing fluid and said conduit and to obtain optimum heating thereof and of the liquid passing through said conduit.

2. A liquid atomizing device comprising (1) a conduit communicating with a liquid reservoir, said conduit having an elongatedstraight tubular wall of large cross-section forthe conveyance of said liquid, (2) a coil spring coaxial with and interiorly of said conduit and in heat exchange relation with the tubular wall of said conduit for agitating and heating the liquid consaid conduit, and (8) a supporting element secured to said reservoir, said supporting element having an arm at one end for supporting said housing in operative position and an arm on the opposite end for securing said device to a permanent support in a permanent location.

HAROLD G. WALTERS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Great Britain Sept. 11,1899 

